Method and apparatus for detecting x-rays having improved noise discrimination

Abstract

A method and apparatus, such as a spectrometer, are provided for facilitating the detection of an gamma signal in a manner that effectively discriminates the gamma signal from noise. A spectrometer may be provided which includes an gamma converter for converting gamma signals which impinge thereupon into corresponding pairs of electrons and positrons. The spectrometer also includes a deflector for separately deflecting the electrons and the positrons as well as electron and positron detectors for separately detecting the deflected electrons and positrons, respectively. As such, an gamma signal can be identified in instances in which the deflected electrons and positrons are detected in coincidence.

1. A spectrometer comprising:
 an gamma converter for converting gamma signals which impinge thereupon into corresponding pairs of electrons and positrons; 
 a deflector, spaced apart from and downstream of the gamma converter, for separately deflecting the electrons and the positrons; and 
 electron and positron detectors for separately detecting the deflected electrons and positrons in order to permit an gamma signal to be identified in instances in which the deflected electrons and positrons are detected in coincidence. 
 
     
     
       2. A spectrometer according to  claim 1  wherein the electron and positron detectors each comprise a plurality of detector elements spaced along a path of the electrons and positrons. 
     
     
       3. A spectrometer according to  claim 2  wherein the detector elements of the electron and positron detectors are positioned in pairs with each pair comprising a detector element of the electron detector and a detector element of the positron detector. 
     
     
       4. A spectrometer according to  claim 3  wherein each pair of detector elements is spaced from the deflector along the path of the electrons and positrons by a different distance, and wherein each detector element of a respective pair is positioned at the same distance from the deflector. 
     
     
       5. A spectrometer according to  claim 1  further comprising a processor for determining that a pair of electrons and positrons detected by the electron and positron detectors, respectively, are coincident based upon a time and location at which the electron and positron detectors detect the electrons and positrons, respectively. 
     
     
       6. A spectrometer according to  claim 5  wherein the processor is configured to identify the gamma signals based upon the pairs of electrons and positrons that are determined to be coincident. 
     
     
       7. A spectrometer according to  claim 6  wherein the processor is further configured to identify the gamma signals without consideration of the electrons and positrons detected by the electron and positron detectors that are not coincident. 
     
     
       8. A spectrometer according to  claim 6  wherein the processor is further configured to decode the signal represented by the pairs of electrons and positrons that are determined to be coincident. 
     
     
       9. A method comprising:
 converting gamma signals into corresponding pairs of electrons and positrons; 
 deflecting the electrons and the positrons separately following propagation of the corresponding pairs of electrons and positrons in a downstream direction; 
 detecting the deflected electrons and positrons separately; and 
 identifying an gamma signal in instances in which the deflected electrons and positrons are detected in coincidence. 
 
     
     
       10. A method according to  claim 9  wherein separately detecting the electrons and positrons comprises separately detecting the electrons and positrons with a plurality of detector elements spaced along a path of the electrons and positrons. 
     
     
       11. A method according to  claim 9  further comprising determining that a pair of electrons and positrons that have been detected are coincident based upon a time and location at which the electrons and positrons are detected. 
     
     
       12. A method according to  claim 11  further comprising identifying the gamma signals based upon the pairs of electrons and positrons that are determined to be coincident in time and location. 
     
     
       13. A method according to  claim 12  wherein identifying the gamma signals comprises identifying the gamma signals without consideration of the electrons and positrons that have been detected, but that are not coincident. 
     
     
       14. A method according to  claim 12  further comprising decoding the signal represented by the pairs of electrons and positrons that are determined to be coincident. 
     
     
       15. A spectrometer comprising:
 an gamma converter for converting gamma signals which impinge thereupon into corresponding pairs of electrons and positrons; 
 a deflector, spaced apart from and downstream of the gamma converter, for separately deflecting the electrons and the positrons; 
 electron and positron detectors for separately detecting the deflected electrons and positrons, wherein the electron and positron detectors each comprise a plurality of detector elements spaced along a path of the electrons and positrons; and 
 a processor configured to determine that a pair of electrons and positrons detected by the electron and positron detectors, respectively, are coincident based upon a time and location at which the electron and positron detectors detect the electrons and positrons, respectively, wherein the processor is also configured to identify the gamma signals based upon the pairs of electrons and positrons that are determined to be coincident. 
 
     
     
       16. A spectrometer according to  claim 15  wherein the processor is further configured to identify the gamma signals without consideration of the electrons and positrons detected by the electron and positron detectors that are not coincident. 
     
     
       17. A spectrometer according to  claim 15  wherein the processor is further configured to decode the signal represented by the pairs of electrons and positrons that are determined to be coincident. 
     
     
       18. A spectrometer according to  claim 15  wherein the electron and positron detectors each comprise a plurality of detector elements spaced along a path of the electrons and positrons. 
     
     
       19. A spectrometer according to  claim 18  wherein the detector elements of the electron and positron detectors are positioned in pairs with each pair comprising a detector element of the electron detector and a detector element of the positron detector. 
     
     
       20. A spectrometer according to  claim 19  wherein each pair of detector elements is spaced from the deflector along the path of the electrons and positrons by a different distance, and wherein each detector element of a respective pair is positioned at the same distance from the deflector. 
     
     
       21. A spectrometer according to  claim 1  wherein said deflector comprises a pair of magnets spaced apart from one another and positioned such that the corresponding pairs of electrons and positrons pass therebetween. 
     
     
       22. A method according to  claim 9  wherein deflecting the electrons and positrons comprises permitting the corresponding pairs of electrons and positrons to pass between a pair of magnets that are spaced apart from one another. 
     
     
       23. A spectrometer according to  claim 15  wherein said deflector comprises a pair of magnets spaced apart from one another and positioned such that the corresponding pairs of electrons and positrons pass therebetween.